Process of finishing cellulosic fabric and product resulting therefrom



United States Patent r 2,763,578 PROCESS OF FINISHING CELLULOSIC FABRIC AND PRODUCT RESULTING THEREFROM John Kenson Simons, Norristown, Pa., assignor to Quaker Chemical Products Corporation, Conshohocken, Pa., a corporation of Pennsylvania No Drawing. Application March 24, 1954, Serial No. 418,462 6 Claims. (Cl. 117145) This invention relates to the finishing of fabrics in order to obtain special effects. In particular it relates to the application of polymeric products to impart various finishes, such as a taffeta finish, for example, to fabrics made of cellulose acetate and regenerated cellulose, such as cuprammoniu-m and viscose rayon.

Fabrics constructed completely or partly of these fibers made be soft and limp or stiff and firm depending on their construction. In order to obtain fabrics with increased stiffness and crispness from the softer construction, it is necessary to apply some kind of finish. For example, the crispness, stiffness, and scroop associated with taffeta-s may be imparted to a cellulose acetate fabric lacking these characteristics by the application of a taffeta finish. Even more stiffness and paperiness are demanded for utilization of the fabric as ribbon; this may be accomplished by applying a ribbon finish.

A ribbon or taffeta finish to be acceptable must impart to the fabric other properties besides crispness, stiffness, paperiness, or scroop. The finish must have such adhesion to the fiber that it does not show mark-off or dusting. It must undergo calendering, hot or cold, with no undesirable eifects on the hand of the fabric. It must not interfere with the cutting of the fabric by means of a hot knife or wire. It must withstand laundering and dry cleaning. It must impart a certain desirable gloss or sheen to the fabric and, obviously, it must not have adverse toxicological or dermatological effects.

Such finishes have in the past been provided by the application of resinous products of the alkyd type made by the condensation reaction of a polybasic acid, such as phthalic acid and polyhydric alcohols, such as glycerol. These resins are supplied and stored in very viscous alkaline solutions. Because of gradual saponification and other detrimental reactions which occur on storage/ these products deteriorate with aging and, therefore, the effects produced by these resins change with their age. In fact, upon prolonged storage, they lose their water solubility and become useless.

An object of the present invention is to provide a means of finishing cellulose acetate and other cellulosic fabrics with resins having much improved storage stability. These resins are addition polymers which are quite resistant to saponification and cannot undergo a gradual deterioration of the kind which takes place with alkyd type materials. Another object is to provide a means of finishing fabrics with polymers which are easily handled as low viscosity emulsions. A further object is to provide a finish with superior qualities in color, mark off, hand and permanence to atmospheric conditions.

A resinous product should possess certain qualifications to be useful for finishing fabrics. It is preferable to apply such resins from an aqueous solution whose viscosity must be low enough to allow for correct mechanical action of the fabric and the finishing machinery. Very few of the known resins which can be dissolved in aqueous media are suitable.

Interpolymers from various polymerizable monomers and polymerizable or unsaturated acids are well known.

Such products as the copolymers of styrene and maleic acid, vinyl methyl ether and ma-leic acid, methyl methacrylate and methacrylic acid have been described and 2,763,578 Patented Sept. 18, 1956 many of them have applications in the textile fields. But although these products have sufficient stability toward saponification, they have disadvantages which have prevented their utilization in certain finishing operations; viz., their solutions at concentrations low enough to give workable viscosities in the bath do not give the desired effect on the fabric and, vice versa, when the bath is made up to a concentration which would probably give the desired effects the viscosity is so high that the fabric cannot be run through it satisfactorily. A further disadvantage of using these products is that they are usually provided as granular or powdery solids which dissolve with difficulty in dilute ammonia or alkalies.

It has been found that finishes of exceptionally fine color and clarity, preserving the fine-st sheen or gloss of an acetate fabric and yielding fabrics with hand characteristics ranging through a heavy fullness: to a thin, crisp paperiness may be obtained by the processes of this invention. Such results are produced by employing an emulsion of an interpolymer of acrylic or methacrylic acid and at least two monomers selected from the group consisting of vinyl acetate, methyl methacrylate, methyl acrylate and ethyl acrylate. These interpolymers are composed of at least three components, e. g., vinyl acetate, an acrylic acid of the formula CH2=C(R)COOH wherein R is H or CH3, or mixtures thereof, together with an ester of such an acid and a lower aliphatic alcohol containing not more than 4 carbon atoms. The proportions of each may be varied within limits hereinafter described. In order that these resins may be applied from alkaline or ammoniacal aqueous solution a certain minimum amount of acrylic acid is desirable. It has been found that at least five mol percent based on the total monomer is necessary. The maximum amount that is desirable is dependent on the Water solubility of the resulting polymer. A maximum percentage which it is undesirable to exceed is 30 mol percent by Weight. The amount of acrylic acid ranges between 5 and 20 mol percent by Weight for satis factory results. Values of 7-10 mol percent by Weight are preferred. i

The choice of other monomers copolymerized with the acrylic acid and the proportions thereof depends upon the quality of the hand desired of the fabric. Vinyl acetate may be used with methyl acrylate or ethyl acrylate, for example, in the proportions by weight of mol percent vinyl acetate, 10 mol percent of methyl or ethyl acrylate and 10 mol percent acrylic acid. The vinyl acetate content in such terpolymers may vary, but should preferably not be less than 50% mol by Weight of the total polymer. The proportion of acrylic acid ester which is incorporated into these resins also may be Widely varied. Values of 5 to 20 mol percent by weight of the total monomer present have been found satisfactory. Seven to ten mol percent are the preferred values.

Interpolymers from acrylic acid or methacrylic acid and a polymerizable monomer are well known. Certain of these products, e. g., methacrylic acid-methyl methacrylate interpolymers, have been suggested for application to textiles as a size, more particularly as a warp size. These products are not suitable for taffeta or ribbon finish because their solutions, at concentrations low enough to give workable viscosities in the bath do not give the desired effects on the fabric. On the other hand, interpoly- Iners of vinyl acetate with acrylic acid have been found to lack sufficient crispness and stiffness when applied as a taffeta finish. Other polymers of various types which have been found to be unsatisfactory for these reasons are: vinyl acetate-maleic anhydride, methyl vinyl ether-maleic 'anhydride, styrene maleic anhydride, vinyl acetate-methyl from vinyl acetate, acrylic acid and vinyl propionate or vinyl Z-ethyl hexoate were found to yield finishes lacking in crispness and paperiness. Satisfactory terpolymers are obtained using vinyl acetate, acrylic or methacrylic acid Alternatively, the resin may be applied to fabrics without forming a solution. The diluted emulsion is applied without adjusting the pH to the alkaline side, using the usual methods of padding, nipping, drying, and calenderand the lower aliphatic esters of acrylic or methacrylic iiig. acid. For example, methyl or ethyl acrylate or methyl The following examples are given for illustrative purmethacrylate may be incorporated in terpolymcrs which poses and are not to limit the invention. yield satisfactory finishes. For specific effects the propyl or butyl esters may be used. For taffeta finishes the most Example 1 desirable third COmPOBEPt is eithfaf methyl acrylate Q This example illustrates the use of varying amounts of ethyl acl'ylate- For a Tlbbon fimsh mfithyl acrylata 1s methyl methacrylate and vinyl acetate with a constant p percentage of acrylic acid in the preparation of emulsions The polymers of this invention are prepared by means f the resins of this invention of the emulsion technique because of the advantages which result from its use, viz., the product is obtained in a finely di id d form which readily reacts with ammonia solutions Emulslon N0 1 2 3 4 5 to form clear or slightly hazy solutions. The emulsion I I 1 itself is of low viscosity and may be handled as a homog f fif composmonofmonomer geneous liquid. V yl acetate 80 80 75 70 60 In carrying out the emulsion polymerization it is posfii3ig3gf{ f{ fi-;; sible to charge all of the components at the start, but it Emulsion formula, percent by weight: has been found that a better product results when a dripg ggl g fg ffi i i f s 1 1 l 1 1 in procedure is used. By this procedure a part (c. g. gogium c iioetyi i l to succinat 1 i 1 1 10%) of the monomer mixture is charged at the start of z gf g g i i; 3' the polymerization and the balance of the monomer to be Monomer mixturc. 28.0 28.0 28.0 23.0 28.0 charged is added gradually to the polymerizing mixture Water as the reaction proceeds. In this way polymers which are completely soluble in ammoniacal solutions are obtained. In preparing the emulsions in this example the follow- Other variations common in the emulsion technique of ing procedure was used: The emulsion stabilizer previemulsion polymerization are possible. For example, it ously dissolved in water, the emulsifier and the persulfate is possible to use well-known emulsifiers and emulsion catalyst were dissolved in the necessary amount of water. stabilizers. Suitable catalysts may be used, for example, The mixture was placed in a glass reaction vessel, fitted peroxides and persulfates. In general, water-soluble catawith a reflux condenser, and stirred mechanically while lysts are preferred. Such variations will be obvious to one tenth of the monomer mixture was added. Heat was those skilled in the art. applied and when refluxing had been well established the The polymeric products above described are obtained balance of the monomer mixture was added over a period as white emulsions with Brookfield viscosities less than 500 of 2 to 5 hours. When all monomer had been added and cp. Addition of ammonia or alkali to the undiluted no further refluxing occurred at a temperature in the emulsion results in the formation of a thick, very viscous emulsion of 95 C. the polymerization was considered solution. If the emulsion is diluted first, addition of difinished. lute alkalies, e. g. KOH, NHrOH, produces clear or slightly The products of this example were diluted by the addihazy, colorless solutions of the corresponding salts of the tion of water to a solids content of 78% by weight. Dicopolymers. The viscosity of the solution of any one lute ammonia was added until the pH was 8.0. Colorless, polymer salt depends on the concentration and the pH. clear to hazy solutions were formed in which pieces of The application to a fabric may be made from an aquecellulose acetate satin were immersed. The wetted cloths ous solution obtained by first diluting the emulsion with were passed between rubber faced rolls to squeeze out water. A thirty percent by weight solids emulsion (1 excess liquid, leaving about 100% wet pick up. These part) may be diluted with 4 parts of water. Dilute amcloths were dried on frames at 250 F. for five minutes. monia is added until the pH rises to 8. The amount of The resulting materials had stiffness, fullness, scroop, and ammonia required will depend on the amount of acrylic the fine sheen required of a affeta finish. By calendering acid which has been incorporated with the resin. The by means of hot rolls the stiifness and paperiness were inaddition of ammonia converts the milky emulsion to a creased. clear or slightly opaque solution. This solution is padded Example 2 on the fabric, the excess removed by passage between rolls. The clutch is dried and may or may not be further proc- Emulsions were P p y the general Prowdllfe essed by calendering, etc., depending on the hand which s ri d in Example 1, using by weight 14 mol per cent is desired. In general, the amount of the copolymer apethyl acrylate and 76 mol per cent vinyl acetate with 10 plied to the f b i is held at as low a quantity as ill mol per cent of acrylic acid in the following formulations. duce the desired hand. This usually ranges from about The products of this example illustrate'the use of different 6 to about 20% by weight of the fabric weight. 0 emulsifiers, emulsion stabilizers and catalysts.

Emulsion N0 6 7 8 9 10 11 12 13 Emulsion Formula, Percent by Weight:

Polyvinyl alchol ("Elvanol 5H2) 1 Polyvinyl alcohol (ElvanoP' 5%22). 1 Hydroxyethyl cellulose (Ccllosize WPHS 0. 0.95 0.95 0. 95 0. 95 0. 95 Alkyl ether of polyethylene glycol Briy 35) 0. 95 0. 95 0.95 Sodium dioctyl suliosuccinate 2.0 1. 0 2, 0

Sodium salt of alkylaryl polyether sultonate ("Trlton" X-200 [28% Potassium persulfate Ammonium persulfate Chelatlng agent (Ethylene diamine tetra acetic acid type). Monomer mix Water Acetate satin treated with these products had the hand of a taffeta fabric.

Example 3 The formulations in this example were polymerized by the procedure described in Example 1.

Emulsion No These products applied to acetate fabrics produced a stiffer finish than those in Example 2. Application of the ammoniacal solution of emulsion No. 15 to regenerated cellulose taffeta ribbon likewise imparted a stiff finish.

Persons skilled in the art of finishing fabrics will appreciate the usefulness and versatility of this invention. It has already been shown how these polymers may be applied to fabric from an emulsion or from a solution formed by addition of ammonia. Other effects are possible by only partly neutralizing the emulsion, or by application with water-repellent compositions, softeners or fire retardant. The use of ammonia solutions results in the application of a resin finish which probably undergoes important changes on curing due to liberation of ammonia. The use of fixed alkalies or the addition of polyvalent salts or bases will give different results: the finish may be made permanently insoluble in Water or it may be given other permanent modifications.

I claim:

1. The process of imparting ribbon and taffeta finishes to a fabric selected from the group consisting of cellulose acetate and regenerated cellulose which comprises impregnating the fabric in a bath containing an interpolymer composed of at least three components consisting by weight of 50-90 mol per cent vinyl acetate, 530 mol per cent of an acrylic acid of the formula wherein R is selected from the group consisting of H and CH3, and 5-20 mol per cent of an ester of said acrylic acid and a lower aliphatic alcohol containing not more than 4 carbon atoms, removing excess of said bath from the fabric and drying the fabric.

2. The process of imparting ribbon and taffeta finishes to a fabric selected from the group consisting of cellulose acetate and regenerated cellulose which comprises impregnating the fabric in a bath containing an interpolymer composed of at least three components consisting by weight of -85 mol per cent vinyl acetate, 7l0 mol per cent of acrylic acid and 7-10 mol per cent of an ester selected from the group consisting of methyl acrylate, ethyl acrylate and methyl methacrylate, removing excess of said bath from the fabric and drying the fabric.

3. The process of imparting ribbon and taffeta finishes to a fabric selected from the group consisting of cellulose acetate and regenerated cellulose which comprises impregnating the fabric in a bath containing an interpolymer composed of at least three components consisting by weight of 80-85 mol per cent vinyl acetate, 7-10 11101 per cent of methacrylic acid and 7l0 mol per cent of an ester selected from the group consisting of methyl acrylate, ethyl acrylate, and methyl methacrylate, removing excess of said bath from the fabric and drying the fabric.

4. The process of imparting ribbon and taffeta finishes to a fabric selected from the group consisting of cellulose acetate and regenerated cellulose which comprises impregnating the fabric in a bath containing an interpolymer composed of at least three components consisting by weight of 80-85 mol per cent vinyl acetate, 7-10 mol per cent of acrylic acid and 7-10 mol per cent of methyl acrylate, removing excess of said bath from the fabric and drying the fabric.

5. The process of imparting ribbon and taffeta finishes to a fabric selected from the group consisting of cellulose acetate and regenerated cellulose which comprises impregnating the fabric in a bath containing an interpolymer composed of at least three components consisting by weight of 80-85 mol per cent vinyl acetate, 7-10 mol per cent methacrylic acid and 710 mol per cent of methyl acrylate, removing excess of said bath from the fabric and drying the fabric.

6. A cellulosic fabric finished in accordance with the process of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS 2,332,896 DAlelio Oct. 26, 1943 2,481,388 Bryant Sept. 6, 1949 2,562,853 Baer July 31, 1951 OTHER REFERENCES Modern Plastics, pages 128 and 129, September 1947. Serial No. 397,138, Fikentscher et al. (A. P. C.), pub-- lished May 11, 1943. 

1. THE PROCESS OF IMPARTING RIBBON AND TAFFETA FINISHES TO A FABRIC SELECTED FROM THE GROUP CONSISTING OF CELLULOSE ACETATE AND REGENERATED CELLULOSE WHICH COMPRISES IMPREGNATING THE FABRIC IN A BATH CONTAINING AN INTERPOLYMER COMPOSED OF AT LEAST THREE COMPONENTS CONSISTING BY WEIGHT OF 50-90 MOL PER CENT VINYL ACETATE, 5-30 MOL PER CENT OF AN ACRYLIC ACID OF THE FORMULA 